A capacitor is an electric circuit element used to store charge temporarily, consisting in general of two metallic plates separated and insulated from each other by a dielectric. Capacitors are useful as a compact source for a high energy pulse.
In many instances, the capacitor takes the form of an aluminum electrolytic capacitor. Existing designs include one or more separators disposed between two or more sheets of aluminum foil. One of the foils serves as the anode of the capacitor, and the other serves as the cathode. Some designs include multiple foils which are interconnected to increase effective size of the anode or cathode.
Electrolytic capacitors often include a dielectric layer formed on one or both of the electrodes. By changing the nature of the dielectric, capacitance can be altered. Higher voltages are possible with improved dielectrics. By improving the design of the dielectric coating, increased capacitor performance is possible.
Varying devices benefit from compact capacitor designs. Implantable cardioverter defibrillators are typically implanted in the left region of the chest or in the abdomen, and include a housing and one or more leads implanted in the patient. Existing implantable cardioverter defibrillator designs include capacitors which can consume 30% of the volume of the housing. A need exists for a smaller device which is capable of delivering patient therapy. One way to obtain a smaller device is to reduce capacitor size.
Thus, implantable cardioverter defibrillators and others devices would benefit from a more compact capacitor. A need exists for an improved capacitor design, including an improved dielectric coating.